Membrane Separation Technology for Instant Coffee Production Process
Background Introduction
The general production process of conventional instant coffee powder includes pretreatment, roasting, grinding, extraction, separation and purification, concentration and drying. Conventional production processes mostly adopt disc separators for the separation and purification of coffee extract, and the purified extract then undergoes thermal concentration. Although the high-speed rotating disc separator can remove most insoluble substances from the solution, a small portion of insoluble matter still remains in the finished product. Sediments will form when brewing coffee, resulting in deteriorated taste. In addition, the subsequent thermal concentration is carried out at relatively high temperatures, which easily causes the decomposition and volatilization of aromatic compounds in coffee and leads to loss of flavor.
Application of Membrane Separation Technology in Instant Coffee Production
Process Flow and Description
Pretreatment: Before formal processing, coffee beans undergo pretreatment such as screening and dedusting, followed by storage for subsequent roasting.
Roasting & Grinding: Roasting is generally classified into light roast, medium roast and dark roast based on roasting intensity. Light-roasted coffee features prominent acidity. As roasting intensity rises, acidity fades while bitterness intensifies; dark-roasted coffee has low acidity and distinct bitterness. Medium roasting is commonly adopted to highlight coffee flavor. Medium-roasted coffee delivers balanced acidity and bitterness with nutty notes and a smooth mouthfeel. Roasted coffee beans are then ground to facilitate subsequent extraction.
Extraction: Roasted coffee contains abundant volatile aromatic compounds that deliver rich coffee aroma. High-temperature extraction tends to cause aroma loss. Therefore, cold-water extraction is adopted to fully preserve the rich coffee aroma.
Disc Separator: The extracted coffee liquid inevitably contains ash and fibrous substances. The high-speed rotating disc separator removes most insoluble substances in coffee solution, which not only improves product quality but also accelerates the filtration rate in the subsequent membrane treatment.
Membrane Filtration: After centrifugation, the coffee extract contains very few insoluble substances, yet it still cannot guarantee zero visible insoluble residues when consumers brew the final product. To further enhance product quality, membrane separation technology is introduced into the impurity removal section of instant coffee production. Relying on the interception effect of precision membranes, insoluble substances in coffee extract can be effectively separated. The treated coffee solution features high clarity, enabling excellent solubility of the final product and greatly improved taste.
Membrane Concentration: After separation and purification, coffee extract usually requires concentration. The concentrated coffee extract with elevated concentration can be directly processed into liquid coffee for sale. If further drying is conducted to produce instant coffee, investment in the drying section can be reduced.
Traditional concentration processes normally employ thermal evaporators. However, high processing temperature easily triggers decomposition and volatilization of aromatic compounds in coffee and impairs product flavor. To tackle this technical challenge, membrane concentration technology is applied to the concentration section of instant coffee production. Leveraging the low-temperature concentration capacity of membranes, the original flavor of coffee extract can be fully retained during concentration.
Freeze Drying: Freeze drying consists of foaming and pre-cooling, quick-freezing tunnel, crushing and granulation, freeze dryer, and fine powder recycling. Freeze drying can completely preserve coffee’s original flavor and color. The quality indicators of final products including color, flavor, density and solubility fully meet consumer requirements.
Advantages of Membrane Separation Technology for Instant Coffee
①The advanced membrane separation technology achieves separation, purification and low-temperature concentration via the precision interception function of membrane elements;
②Pure physical treatment operated under ambient temperature without chemical reactions, avoiding damage to heat-sensitive components and preserving overall flavor;
③Adopts advanced modular design; filter media can be replaced conveniently with simple operation;
④Equipped with on-line regeneration cleaning and drainage devices to cut labor intensity and production costs and boost production efficiency;
⑤Imported foreign membrane elements with complete qualification certificates, featuring long service life and high safety;
⑥The whole set of equipment is made of sanitary-grade materials, complying with GMP standards.
Relevant Applications
Instant Tea Powder: Pu'er tea powder, black tea powder, green tea powder, dark tea powder, etc.
Instant Flower Powder: Rose powder, jasmine powder, etc.
Instant Fruit Powder: Pomelo fruit powder, rosa roxburghii fruit powder, etc.
